JPH1130448A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner, realizing capacity control in a multitude of stages while contriving the reduction of energy consumption as well as the number of constituting components. SOLUTION: When the capacity of 5 HP is to be generated by an outdoor unit 1, an outdoor side ECU 51 operates only a second compressor 4 having the capacity of 6 HP and, at the same time, all of first-third high-pressure side cut-off valves 45-47 and a low-pressure side cut-off valve 48 are opened. Then, a refrigerant pipeline 23 is communicated with another refrigerant pipeline 32 through a communicating pipeline 41 whereby a high-pressure refrigerant gas, flowing through the refrigerant pipeline 23, flows out into the side of the refrigerant pipeline 32 and a part of compressing work, effected by the second compressor 4, is abolished. A capillary tube 49, interposed in the communicating pipeline 41, is designed so as to conduct the flow of high-pressure gas refrigerant per 1 HP upon the operation of the second compressor 4 whereby the outdoor unit 1 generates the capacity of 5 HP.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with a variable capacity compressor and a constant capacity compressor on a heat source side, while reducing energy consumption and the number of constituent parts. The present invention relates to a technology for achieving capability control at a stage.

[0002]

2. Description of the Related Art In recent air conditioners, in order to prevent overshooting and hunting at room temperature during cooling and heating, capacity control is performed on a heat source side (compressor) according to a capacity requirement on a user side (indoor heat exchanger). Is the mainstream. As a method of controlling the capacity of a compressor, there are many methods of converting the frequency of an alternating current using an inverter device and thereby linearly controlling the driving speed of the compressor. According to this method, since the capacity of the compressor can be arbitrarily varied from 0 to the rated point, substantially perfect air conditioning control can be realized. However, the inverter device has various problems, such as inevitable energy loss due to frequency conversion, emission of undesired electromagnetic waves to the environment, and increase in device cost for large-sized devices.

Therefore, Japanese Patent Application Laid-Open No. 8-247560 discloses a variable capacity type compression system in which a power control mechanism and a refrigerant return circuit control the capacity while using a constant speed compressor having a compression mechanism driven at a constant speed. Machine (hereinafter, P
C compressor) has been proposed. The power control mechanism has a valve device attached to the cylinder side wall of the compression mechanism, and by opening this valve device, for example,
The compression work in the first half of the compression stroke is not performed. Further, the refrigerant return circuit, for example, by providing a bypass pipe between the discharge-side refrigerant circuit and the suction-side refrigerant circuit of the compressor, by opening a shut-off valve interposed in this bypass pipe,
A part of the compressed refrigerant is returned to the suction-side refrigerant circuit.

When a PC compressor and a normal constant speed compressor are combined, multi-stage capacity control is performed by operating or stopping both compressors individually or by driving a power control mechanism and a refrigerant return circuit. It becomes possible. For example,
Assuming that the rated capacity of the PC compressor is 4 hp, the rated capacity of the constant speed compressor is 6 hp, the capacity reduction of the PC compressor by the power control mechanism is 2 hp, and the capacity reduction by the refrigerant return circuit is 1 hp, The ability can be switched every 1 horsepower (that is, 10 steps) in the range of 1 to 10 horsepower.

[0005]

By the way, when the above-mentioned refrigerant return circuit is opened, a part of the compressed refrigerant flows back to the suction-side refrigerant circuit, so that the compressor performs useless compression work. . For example, when operating at a capacity of 9 hp, compression work of 1 hp is discarded by the refrigerant return circuit, but energy consumption is substantially the same as when operating at a capacity of 10 hp. As a result, an energy loss equal to or greater than that in the case where the inverter device is used occurs, and this is a factor that makes it difficult to employ a PC compressor. In addition, although it was considered that the capacity control was performed only by the power control mechanism without providing the refrigerant return circuit, in such a case, in the above-described compressor configuration, the capacity switching was performed every two horsepower (that is, five stages). Would. For this reason, in the air conditioner, when the capacity demand on the user side is small (for example, about 1 to 3 horsepower), overshoot or hunting at room temperature is likely to occur, and the user comfort in the space to be air-conditioned is impaired. There is a fear.

Accordingly, the present inventors have developed a PC compressor capable of performing four-stage capacity control with the compressor body, and performing multi-stage capacity control by combining this with a normal constant-speed compressor. Meanwhile, an air conditioner in which the frequency of use of the refrigerant return circuit is reduced has been realized. In other words, a PC compressor capable of switching the capacity every one horsepower in the range of 1 to 4 horsepower is manufactured,
By combining this with a constant speed compressor having a capacity of 6 horsepower, the use of the refrigerant return circuit can be performed only at the time of 5 horsepower operation while performing 10-step capacity control similarly to the above-described conventional apparatus. Was. As a result, the frequency of compression work disposal was reduced and energy consumption was naturally reduced,
This time, since the refrigerant return circuit is used only at the time of 5 hp operation, there has been a problem that the cost performance of the refrigerant return circuit (bypass piping, shutoff valve, joint, etc.) is significantly deteriorated.

The present invention has been made in view of the above circumstances, and has as its object to provide an air conditioner that realizes multi-stage capability control while reducing energy consumption and the number of components. .

[0008]

Therefore, according to the present invention, there is provided a constant capacity compressor and a variable capacity compressor capable of controlling the capacity in a plurality of stages on the heat source side, and the variable capacity compressor is provided. An air conditioner in which a power control mechanism for adjusting the capacity of the air conditioner is driven by a high-pressure refrigerant gas flowing in a high-pressure refrigerant circuit and a low-pressure refrigerant gas flowing in a low-pressure refrigerant circuit, wherein the high-pressure refrigerant circuit and the low-pressure refrigerant A communication pipe that communicates with the circuit; an introduction pipe that branches from the communication pipe and guides the refrigerant gas in the communication pipe to the power control mechanism; and the communication pipe that is closer to the high-pressure refrigerant circuit than a branch position of the introduction pipe. A high-pressure side shut-off valve interposed in a low-pressure side shut-off valve interposed in the communication pipe on the low-pressure refrigerant circuit side from a branch position of the introduction pipe, and a capacity of the variable capacity type compressor. Capacity control means for controlling the driving of the high-pressure side cutoff valve and the low-pressure side cutoff valve based on a predetermined control law, and the capacity control means stops the variable capacity type compressor and When it is necessary to reduce the capacity on the heat source side when the constant capacity compressor is operating, the high-pressure side shut-off valve and the low-pressure side shut-off valve are used to make the communication pipe a refrigerant return pipe. We propose something to be released at the same time.

According to the present invention, for example, the capacity of the constant capacity compressor is relatively larger than the maximum capacity of the variable capacity compressor,
When the capacity requirement on the indoor side becomes a value between the two capacities, the capacity control means simultaneously opens the high-pressure side shut-off valve and the low-pressure side shut-off valve while operating only the capacity type compressor. Then, the high-pressure refrigerant circuit and the low-pressure refrigerant circuit are communicated via the communication pipe, and a part of the capacity of the constant capacity compressor is discarded, so that the indoor capacity requirement is satisfied.

According to a second aspect of the present invention, in the air conditioner of the first aspect, the variable capacity compressor is provided between the capacity of the constant capacity compressor and the maximum capacity of the variable capacity compressor. The present invention proposes a compressor in which there is a difference in capacity of approximately two stages and the amount of decrease in capacity when the communication pipe is a refrigerant return pipe is substantially equal to the amount of increase or decrease in capacity per step of the variable capacity compressor.

In the present invention, the capacity control means appropriately controls the operation of the constant capacity type compressor and the variable capacity type compressor, and controls the opening and closing of the high pressure side cutoff valve and the low pressure side cutoff valve, so that the heat source side is controlled. Can be controlled stepwise from a minimum value to a maximum value.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an air conditioning system including one outdoor unit 1 and a plurality of indoor units 2. In FIG. 1, a refrigeration cycle is indicated by a solid line, and a control / signal system is indicated by a dashed line. Is shown.

On the side of the outdoor unit 1, there are provided first and second compressors 3 and 4, an electromagnetic four-way valve 5, an outdoor heat exchanger 6, an electric fan 7, an accumulator 8, an oil separator 9, and the like. . An electric expansion valve 11, an indoor heat exchanger 12, an electric fan 13, and the like are installed on each indoor unit 2 side. Among these devices, those constituting a refrigeration cycle are connected by refrigerant pipes 21 to 36 provided for the flow of gas refrigerant or liquid refrigerant. In the figure,
Non-return valves 15 and 16 for preventing the refrigerant from flowing back to the compressors 3 and 4 are interposed in the refrigerant pipes 21 and 22, respectively.

In the case of this embodiment, the refrigerant pipe 23 (high-pressure refrigerant circuit) and the refrigerant pipe 32 (low-pressure refrigerant circuit) are connected by a communication pipe 41, and further from the communication pipe 41, in order from the refrigerant pipe 23 side. First to third introduction pipes 42 to 44
Has branched. Each of the first to third introduction pipes 42 to 44 is connected to the first compressor 3 as a drive source of a power control mechanism described later. In addition, the communication pipe 41
The first to third high pressure side shut-off valves 4 of normally closed type
5 to 47 are interposed, and a normally-closed low-pressure side shutoff valve 48 is also interposed from the branch line of the third introduction pipe 44 to the refrigerant pipe 32. In the figure, reference numeral 49 denotes a capillary tube which is interposed between the low pressure side shutoff valve 48 and the refrigerant pipe 32 in the communication pipe 41.

The outdoor unit 1 includes an outdoor control unit (hereinafter referred to as an outdoor ECU) including a CPU, an input / output interface, a ROM, a RAM, and the like.
51) are provided. The outdoor ECU 51 includes:
Based on input information from a built-in control program and various sensors (not shown), the compressors 3, 4 and the four-way valve 5, the electric fan 7, and the shut-off valves 45 to 48 are drive-controlled.

On the other hand, in each indoor unit 2, an indoor control unit (hereinafter referred to as an indoor ECU) 53 including a CPU, an input / output interface, a ROM, a RAM and the like is installed. Indoor ECU5
2 controls driving of the electric expansion valve 11 and the electric fan 13 based on input signals from a built-in control program, a remote controller (not shown), various sensors, and the like, and communicates with the outdoor ECU 51 via the bus line 55. To exchange signals with each other.

In this embodiment, the first and second compressors 3 and 3
Reference numeral 4 denotes an electric twin rotor type constant speed compressor having a pair of upper and lower rotary compression elements. The rated output of the first compressor 3 is 4 hp, and the rated output of the second compressor 4 is 6 hp. ing. The first compressor 3 is a PC compressor provided with a power control mechanism, and can switch the output between 1 to 4 horsepower every one horsepower.

The structure and operation of the power control mechanism according to the present embodiment will be described below.

The compression mechanism 61 of the first compressor 3 has a pair of upper and lower cylinders 69 and 70 sandwiched between a main frame 65 and a bearing plate 67, and both cylinders 69, as shown in FIG. , 70 and a pair of upper and lower cylinder chambers 73, 7 defined by the intermediate plate 71.
5 and a pair of upper and lower rotors 77 and 79 which eccentrically rotate with a phase difference of 180 ° while slidingly contacting the inner peripheral surfaces of the two cylinder chambers 73 and 75. In the figure, reference numeral 80 denotes a compressor casing.

The power control mechanism 81 communicates the two cylinder chambers 73 and 75 at three communicating portions (portions which are out of phase by 90 ° and 180 ° with respect to a vane described later). A valve hole 83 penetrating vertically through the outer periphery of the intermediate plate 71, a pair of upper and lower piston valves 85, 86 slidably held in the valve hole 83,
A main component is a valve spring (compression coil spring) 87 that urges the pumps 86 away from each other. In the intermediate plate 71, the inner diameter of the valve hole 83 is smaller than the outer diameter of the piston valves 85 and 86 so as to form stoppers for the piston valves 85 and 86. Further, the valve spring 87 is completely compressed when a high pressure (for example, 20% of the maximum discharge pressure of the first compressor 3) acts on the pressure receiving surfaces of the piston valves 85 and 86 at a predetermined value or more. Is set.

The valve hole 83 communicates with the two cylinder chambers 73 and 75 through a pair of communication holes 88 and 89 formed near the intermediate plate 71. In both cylinders 69, 70 and intermediate plate 71, valve holes 83 are provided.
A gas refrigerant from the introduction pipe 42 (43, 44) is introduced into the refrigerant introduction hole 91. Further, communication recesses 93 and 94 are formed in the main frame 65 and the bearing plate 67 to communicate the valve hole 83 and the coolant introduction hole 91, respectively.

When low-pressure refrigerant gas is introduced into the refrigerant introduction hole 91, the piston valves 85 and 86 are actuated by the spring force of the valve spring 87, as shown in FIG. Pressed to. As a result, both cylinder chambers 73 and 75
The gas refrigerant flows through the communication holes 88 and 89, the valve hole 83, and the check valve 90, and flows out of the compression space of one cylinder chamber 75 (73) into the suction space of the other cylinder chamber 73 (75). On the other hand, when high-pressure refrigerant gas is introduced into the refrigerant introduction hole 91, a high pressure acts on the pressure receiving surfaces of the piston valves 85 and 86, and the valve spring 87 is compressed. It comes into contact with the plate 71. As a result, both piston valves 85, 8
The communication holes 88 and 89 are closed by the outer peripheral surface of 6, and the communication between the two cylinder chambers 73 and 75 is stopped.

FIG. 4 is a schematic diagram showing the arrangement of the power control mechanism 81 with respect to the compression mechanism 61. As described above, the power control mechanism 81 is disposed at a position that is 90 ° and 180 ° out of phase with respect to the vane 95, and the first introduction pipe 42 is provided in the power control mechanism 81 on the discharge port 97 side. Connect and Vane 9
The second introduction pipe 43 is connected to the power control mechanism 81 facing the power supply 5, and the third introduction pipe 44 is connected to the power control mechanism 81 on the suction port 98 side.

In the present embodiment, when the power control mechanism 81 is operated, the outdoor ECU 51 appropriately controls the driving of the first to third high-pressure cutoff valves 45 to 47 and the low-pressure cutoff valve 48. For example, first to third high pressure side shutoff valves 45 to 45
If the low pressure side shut-off valve 48 is closed (OFF operation) by opening the 47 (ON operation) and the low pressure side shut-off valve 48 is closed, the high pressure refrigerant gas in the refrigerant pipe 23 is controlled by the power control via the first to third introduction pipes 42 to 44. The first compressor 3 is introduced into the mechanism 81, whereby the communication between the two cylinder chambers 73, 75 is completely shut off, and the first compressor 3 performs a compression work of 4 hp during its operation. In this state, the low-pressure side shutoff valve 48 is opened (ON
Operation), the low-pressure refrigerant gas in the refrigerant pipe 32 becomes the third
The power is introduced into the power control mechanism 81 on the suction port 98 side through the introduction pipe 44, whereby the communication between the two cylinder chambers 73 and 75 is cut off by 3/4, and the first compressor 3 is turned off during operation. It will do the work of compressing horsepower.

When the third high-pressure side shutoff valve 47 is further opened (ON operation) from this state, the power control in which the low-pressure refrigerant gas in the refrigerant pipe 32 faces the vane 95 via the second introduction pipe 43. It is also introduced into the mechanism 81, whereby the communication between the two cylinder chambers 73 and 75 is cut off by half, and the first compressor 3 performs a compression work of 2 hp during its operation. Then, when the second high-pressure side shut-off valve 47 is further opened (ON operation) from this state, the low-pressure refrigerant gas in the refrigerant pipe 32 becomes the first to third introduction pipes 42 to 44.
, The communication between the two cylinder chambers 73 and 75 is cut off by ４, and the first compressor 3 performs 1 hp compression work during its operation. become.

The outdoor ECU 51 provides the outdoor unit 1 with 1
When the capacity of 10 to 10 hp is generated, the operation control of the first and second compressors 3 and 4 and the drive control of the power control mechanism 81 are performed as follows. That is, while operating only the first compressor 3, the first to third high-pressure side shutoff valves 45 to 47
By driving and controlling the low-pressure side shut-off valve 48 in the above-described procedure, it is possible to obtain the capability for each 1 hp between 1 and 4 hp. In addition, if only the second compressor 4 is operated, a capacity of 6 horsepower can be naturally obtained. And
While operating the first and second compressors 3 and 4 simultaneously, the first
By driving and controlling the third to third high pressure side shutoff valves 45 to 47 and the low pressure side shutoff valve 48, it is possible to obtain a capacity for each 1 hp from 7 to 10 hp.

When the outdoor unit 1 is to have a capacity of 5 hp, the outdoor ECU 51 operates only the second compressor 4 and simultaneously operates the first to third high-pressure side shutoff valves 45 to 45.
47 and the low pressure side shutoff valve 48 are all opened (ON operation). Then, the refrigerant pipe 23 and the refrigerant pipe 32 are communicated with each other by the communication pipe 41, and the high-pressure refrigerant gas flowing through the refrigerant pipe 23 flows out to the refrigerant pipe 32 side, and one of the compression work performed by the second compressor 4 is performed. Parts will be discarded. That is, the communication pipe 41 includes the first to third high-pressure side shutoff valves 45 to 4.
When both the valve 7 and the low-pressure side shutoff valve 48 are opened, the operation is equivalent to that of the refrigerant return circuit in the conventional device. The capillary tube 49 interposed in the communication pipe 41 is connected to the first tube 4 when the second compressor 4 is operating.
Since the high-pressure gas refrigerant corresponding to the horsepower is set to flow, the outdoor unit 1 generates a capacity of 5 horsepower. FIG. 5 shows the capacity of the outdoor unit 1 and
ON / O of the second compressors 3 and 4 and the shutoff valves 45 to 48
It is a table which shows the relationship with FF state.

As described above, in the air conditioning system of the present embodiment, the communication pipe and the shut-off valve for the power control mechanism also have the function of the refrigerant return circuit. There is no need to provide such a device, and the device configuration can be simplified and costs can be reduced.

The description of the specific embodiment has been completed.
Aspects of the present invention are not limited to this embodiment.
For example, in the above-described embodiment, the present invention is applied to an air conditioning system including one variable capacity compressor and one fixed capacity compressor, but a plurality of fixed capacity compressors are provided. Etc. may be applied. Further, in the above embodiment, the power control mechanism of the four-stage control is provided in the twin rotor type constant speed compressor. However, the power control by the power control mechanism may be three or less stages or five or more stages. A machine having a compression mechanism of a triple rotor or more may be used. Further, as for the structure of the power control mechanism, various structures are conceivable, for example, a communication pipe is provided outside the compressor casing, and other specific configurations in the refrigeration cycle also deviate from the gist of the present invention. It can be changed appropriately as long as it is not within the range.

[0030]

As described in detail above, claim 1 is as follows.
According to the invention, the heat source side has a constant capacity compressor and a variable capacity compressor capable of controlling the capacity in a plurality of stages, and a power control mechanism for adjusting the capacity of the variable capacity compressor is a high pressure refrigerant circuit. An air conditioner driven by a high-pressure refrigerant gas flowing through the inside and a low-pressure refrigerant gas flowing through the low-pressure refrigerant circuit, comprising: a communication pipe for communicating the high-pressure refrigerant circuit with the low-pressure refrigerant circuit; and the communication pipe. And a high-pressure side shut-off valve interposed in the communication pipe on the high-pressure refrigerant circuit side from a branch position of the introduction pipe, the introduction pipe guiding the refrigerant gas in the communication pipe to the power control mechanism. A low-pressure side shut-off valve interposed in the communication pipe on a side of the low-pressure refrigerant circuit from a branch position of the introduction pipe, and the high-pressure side shut-off valve and the low-pressure shut-off valve for adjusting the capacity of the variable capacity compressor. And a capacity control means for driving and controlling the shutoff valve based on a predetermined control law, wherein the capacity control means is provided when the variable capacity type compressor is stopped and the constant capacity type compressor is operating. When it is necessary to reduce the capacity on the heat source side, the high-pressure side shut-off valve and the low-pressure side shut-off valve are simultaneously opened in order to make the communication pipe a refrigerant return pipe. Therefore, members for configuring a dedicated refrigerant return circuit, such as a bypass pipe and a shutoff valve, are not required, so that the device configuration can be simplified and the cost can be reduced.

Further, according to the invention of claim 2, according to claim 1,
In the air conditioner, there is a capacity difference of approximately two stages in the variable capacity type compressor between the capacity of the constant capacity type compressor and the maximum capacity of the variable capacity type compressor, and the communication pipe is Since the amount of capacity decrease in the case of the refrigerant return pipe and the amount of capacity increase / decrease per stage of the variable capacity compressor are assumed to be substantially the same, the capacity control means uses a constant capacity compressor and a variable capacity compressor. , And the opening and closing control of the high-pressure side shut-off valve and the low-pressure side shut-off valve is appropriately performed, whereby the capability of the heat source side can be controlled stepwise from the minimum value to the maximum value.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an embodiment of an air conditioning system according to the present invention.

FIG. 2 is a half vertical sectional view showing the structure and operation of a power control mechanism.

FIG. 3 is a half vertical sectional view showing the structure and operation of a power control mechanism.

FIG. 4 is a schematic diagram showing an arrangement of a power control mechanism with respect to a compression mechanism.

FIG. 5 is a table showing the relationship between the capacity of the outdoor unit and the ON / OFF states of the first and second compressors and each shut-off valve.

[Explanation of symbols]

 Reference Signs List 1 outdoor unit 2 indoor unit 3 first compressor (variable capacity compressor) 4 second compressor (constant capacity compressor) 23 refrigerant pipe (high pressure refrigerant circuit) 32 refrigerant pipe (low pressure refrigerant circuit) 41 communication pipe 42 1st communication pipe 43 2nd communication pipe 44 3rd communication pipe 45 1st high pressure side cutoff valve 46 2nd high pressure side cutoff valve 47 3rd high pressure side cutoff valve 48 low pressure side cutoff valve 49 Capillary tube 51 Outdoor ECU

Claims (2)

[Claims] 1. A high-performance refrigerant circuit having a constant capacity compressor and a variable capacity compressor capable of controlling the capacity in a plurality of stages on a heat source side, and a power control mechanism for adjusting the capacity of the variable capacity compressor. An air conditioner driven by a high-pressure refrigerant gas flowing through the low-pressure refrigerant gas and a low-pressure refrigerant gas flowing in the low-pressure refrigerant circuit, comprising: a communication pipe that communicates the high-pressure refrigerant circuit and the low-pressure refrigerant circuit; and An introduction pipe that branches and guides the refrigerant gas in the communication pipe to the power control mechanism; a high-pressure side cutoff valve interposed in the communication pipe on the high-pressure refrigerant circuit side from a branch position of the introduction pipe; A low-pressure side shut-off valve interposed in the communication pipe on the low-pressure refrigerant circuit side from a branch position of the pipe; and a high-pressure side shut-off valve and the low-pressure side to adjust the capacity of the variable capacity compressor. And a capacity control means for driving and controlling the shutoff valve based on a predetermined control law, wherein the capacity control means is provided when the variable capacity type compressor is stopped and the constant capacity type compressor is operating. An air conditioner characterized by opening the high-pressure side shut-off valve and the low-pressure side shut-off valve at the same time in order to make the communication pipe a refrigerant return pipe when it becomes necessary to reduce the capacity on the heat source side. 2. The variable capacity compressor has a capacity difference of approximately two stages between the capacity of the constant capacity compressor and the maximum capacity of the variable capacity compressor, and the communication pipe is connected to a refrigerant. 2. The air conditioner according to claim 1, wherein a capacity reduction amount in the case of a return pipe is substantially equal to a capacity change amount per one stage of the variable capacity compressor. 3.